Add the function dump_stack_print_cmdline() which can be used by arch
code to print the command line of the current processs. This function
is useful in arch code when dumping information for a faulting process.
Wire this function up in the dump_stack_print_info() function to include
the dumping of the command line for architectures which use
dump_stack_print_info().
As an example, with this patch a failing glibc testcase (which uses
ld.so.1 as starting program) up to now reported just "ld.so.1" failing:
do_page_fault() command='ld.so.1' type=15 address=0x565921d8 in libc.so[f7339000+1bb000]
trap #15: Data TLB miss fault, vm_start = 0x0001a000, vm_end = 0x0001b000
and now it reports in addition:
ld.so.1[1151] cmdline: /home/gnu/glibc/objdir/elf/ld.so.1 --library-path /home/gnu/glibc/objdir:/home/gnu/glibc/objdir/math:/home/gnu/
/home/gnu/glibc/objdir/malloc/tst-safe-linking-malloc-hugetlb1
Josh Triplett noted that dumping such command line parameters into
syslog may theoretically lead to information disclosure.
That's why this patch checks the value of the kptr_restrict sysctl
variable and will not print any information if kptr_restrict==2, and
will not show the program parameters if kptr_restrict==1.
Signed-off-by: Helge Deller <[email protected]>
---
include/linux/printk.h | 5 +++++
lib/dump_stack.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index cf7d666ab1f8..5290a32a197d 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -191,6 +191,7 @@ u32 log_buf_len_get(void);
void log_buf_vmcoreinfo_setup(void);
void __init setup_log_buf(int early);
__printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
+void dump_stack_print_cmdline(const char *log_lvl);
void dump_stack_print_info(const char *log_lvl);
void show_regs_print_info(const char *log_lvl);
extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold;
@@ -262,6 +263,10 @@ static inline __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...)
{
}
+static inline void dump_stack_print_cmdline(const char *log_lvl)
+{
+}
+
static inline void dump_stack_print_info(const char *log_lvl)
{
}
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 83471e81501a..38ef1067c7eb 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -14,6 +14,7 @@
#include <linux/kexec.h>
#include <linux/utsname.h>
#include <linux/stop_machine.h>
+#include <linux/proc_fs.h>
static char dump_stack_arch_desc_str[128];
@@ -45,6 +46,37 @@ void __init dump_stack_set_arch_desc(const char *fmt, ...)
#define BUILD_ID_VAL ""
#endif
+/**
+ * dump_stack_print_cmdline - print the command line of current process
+ * @log_lvl: log level
+ */
+void dump_stack_print_cmdline(const char *log_lvl)
+{
+ char cmdline[256];
+
+ if (kptr_restrict >= 2)
+ return; /* never show command line */
+
+ /* get command line */
+ get_task_cmdline_kernel(current, cmdline, sizeof(cmdline));
+
+ if (kptr_restrict == 1) {
+ char *p;
+
+ /* if restricted show program path only */
+ p = strchr(cmdline, ' ');
+ if (p) {
+ *p = 0;
+ strlcat(cmdline,
+ " ... [parameters hidden due to kptr_restrict]",
+ sizeof(cmdline));
+ }
+ }
+
+ printk("%s%s[%d] cmdline: %s\n", log_lvl, current->comm,
+ current->pid, cmdline);
+}
+
/**
* dump_stack_print_info - print generic debug info for dump_stack()
* @log_lvl: log level
@@ -62,6 +94,8 @@ void dump_stack_print_info(const char *log_lvl)
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version, BUILD_ID_VAL);
+ dump_stack_print_cmdline(log_lvl);
+
if (dump_stack_arch_desc_str[0] != '\0')
printk("%sHardware name: %s\n",
log_lvl, dump_stack_arch_desc_str);
--
2.37.1